STRANGENESS AND COLD DENSE MATTER

WCU-YITP

Mannque Rho (Saclay & Hanyang) A personal overview: April 21, 2011

STRANGENESS IS “STRANGE”

The strange (s) quark mass is NEITHER too big nor too small. So, one might say the strange quark is BOTH light and heavy!

“Light” → chiral perturbation theory

“Heavy” → Callan-Klebanov kaon-skyrmion bound state hyperon

PDG

Scoccola et al 1989

CK WORKS WELL FOR HYPER-ONS

Wrap “heavy kaon” with a skyrmion

AMBIDEXTERITY OF STRANGE-NESS

“One can go smoothly from `massive’ kaon to `chiral’ kaonin the baryon structure”

Kaplan & Klebanov 1990

RISE AND FALL OF KN SIGMA TERM

A measure of how strangeness enters in nuclearprocesses is in the KN sigma term

Strange quark contributes to the nucleon mass

Old days (pre-lattice): ≈ 350 MeVNow (post-lattice): ≈ 50-60 MeV

Implies the sigma term drops from ∼400 MeV toas low as ∼120 MeV!

dra Dramatic effect?? Talk by H.K. Lee

KAON IN DENSE BARYONIC MATTER

Raging fight/controversy: Kaon is strongly bound vs. weakly bound in nuclear medium

I have no clean argument to rule out one over the other.

What does nature say? According to Gal: Nature is nonlinear!

“STRANGE”PHENOMENON

Kurt Vonnegut, “Cat’s Cradle”

“Strange” things happen with strangeness in densematter in ignorance of what’s really going on in densityat n > n0 .

Alternative scenarios

“Standard” model: Anchored on the Weinberg-Tomozawa term;Coupled channels, unitarity etc.

Kaon bound to skyrmion matter:Anchored on Wess-Zumino anomaly term

NON-STANDARD OBSERVATION

Dense matter simulated with skyrmions on crystalundergoes phase transition from skyrmion matterto half-skyrmion matter, what looks like apseudo-gap phase, at n1/2 > n0 . What’s this in thestandard picture? Georgi’s vector symmetry?

It triggers an additional K-nuclear attraction not seen instandard picture.

Byung-Yoon Park’s talk

APPEARANCE OF FRACTIONIZED SKYRMIONS

skyrmion

half-skyrmion

Simulate dense matter by putting skyrmions in FCC crystals and squeeze them: ½-skyrmions in CC appear at n1/2

B.Y. Park et al,1999

skyrmions Half-skyrmions

ALSO IN HQCD: “DYONIC SALT”

Increasing density

Instantons: FCC

½ instantons(dyons): BCC

Sin, Zahed, R., Phys. Lett. B689, 23 (2010)

Dyons are bound by ~ 180 MeV.

“PHASE”STRUCTURE

Sigma model

HLS model

The ½-skyrmion phase at n n1/2 is characterized by

Rough estimate: n1/2 ~ (1.3 – 2) n0

n1/2ndeconf

i.e. “vector mode”

Is chiral symmetry restored?

No! No-go theorem a la Cohen.

CHARACTER OF ½-SKYRMION PHASE

on the “average” but fp ≠ 0

Nucleon mass scales only slightly

≠ 0

But

Vector meson mass scales

g is the order parameter!

POSSIBILITY FOR EMERGENT PARITY-DOU-BLET STRUCTURE

Dilaton c + HLS+ parity-doublet quasiquarks→ dilaton limit → VM fixed point

Constituent quark mass:

Dilaton limit:

VM fixed point:

Much like the properties of the skyrmion crystal

More on this matter later

Dynamicallygenerated

A la DeTar & Kunihiro 89Jido et al…1998- …

Beane, van Kolck, Weinberg

HY

APPLICATION: STRANGE GOINGS-ON IN COMPRESSED MATTER

Insert anti-kaon in half-skyrmion matter

Skyrmion-1/2-skyrmion background

Ignore kaon back-reaction onto (half-)skyrmion matter

J.I. Kim, B.Y. Park, R. 2009

THERE IS UNEXPECTED(!) ATTRACTION IN ½-SKYRMION MATTER

△B ~ 50-60 MeV

Is this what Akaishiand Yamazaki need for dense kaonic matter ?

Shrinkage?

DB

ANTI-KAON “ROAMING” THROUGH ½-SKYRMION MATTER: WESS-ZUMINO TERM

How to measure isospin spirals?

Monte Carlo simulation

Observation

“Chiral magnetic spirals”

Something similar in Nature

HOW ABOUT ANALOGY TO “MAGNETIC SPI-RALS” WITH SPIN → ISOSPIN?

Pfleiderer & Rosche,Nature, 17 June 2010

Chiral magnetic spiralsDzyaloshinsky-Moriya interaction

TENSOR FORCES ARE DRASTICALLY MODIFIED IN THE ½-SKYRMION PHASE

For density n n1/2 :

n=n0

n=2n0

n=0+p r

Above n1/2, the r tensor gets “killed,” enabling the pions (p0’s) to condense → pionic crystal in dense neutron matter ( e.g., Pandharipande and Smith 74).

Decreasing tensor Increasing tensor

n1/2

For density n < n1/2 :

“standard” nuclear physics

,

Effect on symmetry energy

Scaling prediction

This prediction could be checked or falsified atFAIR or even RIB (e.g., KoRIA) machines

½-skyrmion Scaling prediction

≈

AND AT HIGHER DENSITY?

See “dilaton limit” below!

Do kaons condense In dense matter?

Yes schoolNo school

K-p p

The L(1405) plays an essential role in forming "Kbar Nuclear Clusters" (KNC).

A new window to Nuclear Physics would be opened up through the investigation of KNC.

Experimental information on L(1405) is virtually important to establish the "super-strong nuclear force" (SSNF).

Much ado about (1405) L Y. Akaishi 2010

down

strange

1st generation

strange

2nd generation

uck

Naming by K. Nishijima

wan

The s quark plays a leading rolein forming a dense and cold nucleus.

Strangeness nuclear physics Swan nuclear physicsT. Yamazaki & Y. A.

Ice-9?

K- + p

MeV -27K EMeV 04Γ

1 2 3 r fm0

-50

-200

-300

-400

-500

nuclKU

MeV

L(1405)S+p

L+p

K- + pp

MeV -48K EMeV 61Γ

1 2 3 r fm0

-50

-200

-300

-400

-500

nuclKU

MeV

H2KS+p

L+p

K- + 3He

MeV -108K EMeV 02Γ

1 2 3 r fm0

-50

-200

-300

-400

-500

nuclKU

MeV

H3K

S+p

L+p

Y. Akaishi & T. Yamazaki, Phys. Rev. C 65 (2002) 044005

Shrinkage!

A. Dote et al.Yes, but for skeptics “Ice-9”

8BE 　　　　　　　　 8BEK-

7 fm

Density (/fm^3) 0.0 0.41 0.83

Density (/fm^3) 0.0 0.10 0.20

AntisymmetrizedMolecularDynamics calculation　　　　　A. Dote, H. Horiuchi, Y. Akaishi & T. Yamazaki, Phys. Lett. B590 (2004) 51.

Dense & Cold

ppnK-

“Challenging problem” !

pp

n

K-

1.5 fm

rN(0) = 9r0

rNav= 3r0

1.2 fm

MeV20,MeV108 E

MeV25,MeV6169 EExp.

DB ｔｈ -ex ~ 60 MeV

Chiral restoration ?

Relativistic effect ?

Y. Akaishi 2010

“ICE-9”TO SKEPTICS

Ice-nine is a fictional material appearing in Kurt Vonnegut's novel Cat's Cradle. It is supposed to be a more stable polymorph of water than common ice (Ice Ih) which instead of melting at 0 degrees Celsius (32 degrees Fahrenheit), melts at 45.8 °C (114.4 °F).

When ice-nine comes into contact with liquid water below 45.8 °C (which is thus effectively supercooled), it acts as a seed crystal, and causes the solidification of the entire body of water which quickly crystallizes as ice-nine.

Far below L(1405) pole, L(1405) is irrelevant !

One has to start below L(1405) pole !

31

Chang-Hwan Lee

Obscure RGE argument (‘95)by Lee, Sin, R. supports this scenario

But (1405)L is irrelevant for kaon condensation

What does Gal say? No condensation!

Number of kaons

Because of the w repulsion between constituent u quarks in anti-kaons (us).

BUT LATTICE SUGGESTS OTH-ERWISE

Tree-order chiral perturbation calculationreproduces lattice result , which meanshigher-order terms (loops and counter terms)sum to negligible A miracle!!

Detmold et al, 2008

D(ILATONIC)HLS ALSO SAYS OTHERWISE

C. Sasaki, W.-G.Paeng et al 2011

DHLS

HLS is a gauge-equivalent nonlinear sigma model, applicable up to the scale of the vector meson mass ∼ mV ∼ 700-800 MeV and allows chiral perturbation treatment for the case when mV

* /mp becomes ∼ O(1). DHLS takes into account a low-mass scalar degree of

freedom in terms of a dilaton c figuring in the QCD trace anomaly.

Introduce fermionic degrees of freedom in terms of quasi (constituent) quarks or baryons so as to treat dense baryonic matter.

“DILATON LIMIT (DL)”One-loop RGE analysis (W.-G. Paeng et al) indicates thatthere is a “dilaton limit” fixed point approaching the Gell-Mann-Levy-type linear sigma model:

DL fixed point

Consequences

DL fixed point ⇔ VM fixed point?

q

q

q

q

, w r

DL: Suppression of vector exchanges

DL IMPLIES The repulsive interaction between antikaons gets

suppressed as density increases to the dilaton limitThe attractive antikaon-nucleon interactions due to the

exchange of vector mesons ( , )w r get also suppressed.

But the scalar ( (c ) s exchange between nucleon and antikaon with gsqq≈gpqq takes over the attraction lost.

And The famous “hard-core” repulsion in nuclear interactions

should soften at high density. Relevance to 2 solar mass star?

Demorest et al, Nature 467, 1081 (2010)

“All equations of state with kaon condensation, hyperons … other than strongly interacting strange quark matter are ruled out by this star” !!

PSR J1614-2230 (1.97 M⊙)C.-H. Lee’s talk

Ozel, Baym and Guver 2011

Softeningrepulsionhelpful?

Caveat:Lattimer objection

Exotica

nuclearmatter (NM)

NM+kaon condensed (KC)

NM+KC+s quark matter

(K. Kim, H.K. Lee, MR)

3-layer: nuclear-kaon condensed-s-quark matter

H.K. Lee’s talk

END LET US GET STARTED